The quality of woven fabric depends upon the number of defects left in the fabric after the manufacturing process. Weaving involves repeating in sequence the operations of shedding, picking, and battening. All these processes are typically carried out by a loom. Shedding is the process by which warp yarns are raised or lowered to produce a space, known as the shed, through which a filler yarn may be passed. Picking is the process of inserting a filler yarn through the shed, such that it intersects the warp threads. Battening is the process of pressing the filler yarn against the fell, where the newly woven fabric is formed.
Defects developing during any of these processes determine the quality of the finished fabric. Typically, the finished fabric is inspected for faults according to industry standards. For example, in the standard four-point system of fabric inspection, penalty points being given for detected defects. The size of the penalty depends also upon the length of the defect with 1 penalty point being given to defects of 3 inches or less, 2 penalty points being given to defects of between 3 to 6 inches, 3 penalty points being given to defects of between 6 to 9 inches and 4 penalty points being given to defects of above 9 inches. The quality of the batch of cloth is described by the number of penalty points per 100 yards of inspected cloth, with up to 40 points being generally considered an acceptable defect rate. Apart from the four-point system described above, other standards, such as the more complicated ten-point system or the Dallas System for knitted fabric, may be used to measure the quality of cloth.
Generally, a sample size of at least ten percent of rolls of finished fabric are inspected. Faults in uninspected rolls are typically left undetected until the cloth is sold on. Furthermore, although such defect inspections are standardized as far as possible, it is noted that they depend upon the subjective assessment of the inspector. What one inspector may consider to be a defect, another inspector may consider to be acceptable. Accordingly, the same roll of cloth may be assessed very differently by different inspectors regardless of its actual quality.
It will be appreciated therefore that there is a need for an improved measure of the quality of woven fabric which may be used as an objective industry standard. The systems and methods described herein come to address this need.